“Ki Teze la’milchama al oivecha, u’netano Hashem Elokecha b’yadecha vshavita shivyo –
when you will go out to war against your enemies, and hashem, your God, will deliver him into your hand, and you will capture his captivity”
(Devarim 21:10)
The Or Hachaim (Rabbi Haim Ben Attar) explains:
“Ki Tetze la’milchama al oivecha” – If you go out to war against (literally on/upon) your enemies” – is related to the war against our yetzer ha’rah (evil inclination) rather than an actual physical war.
Every soul descends from the upper world and becomes enclothed into a body in this physical world. This descent is for the explicit purpose of fighting against the yetzer hara. Each person is faced with a yetzer hara specific to him. His fight against it is his personal task in the overall tikkun olam (repair of the world).
Why is this fight called a “milchama“, a war? Because this kind of war against yetzer hara requires a tremendous amount of strength.
What is the meaning behind “al oivecha – on (or upon) your enemy” rather than “neged -against” your enemy? The war against the yetzer hara is not a temporary war but an ongoing, permanent war. If you don’t constantly rise up to combat him, he will prevail over you, chas v’shalom (Heaven forbid).